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The examination of two 2010 Chandra ACIS exposures of the Circinus galaxyresulted in the discovery of two pulsators: CXO J141430.1-651621 and CXOUJ141332.9-651756. We also detected 26-ks pulsations in CG X-1, consistentlywith previous measures. For ~40 other sources, we obtained limits on periodicmodulations. In CXO J141430.1-651621, which is ~2 arcmin outside the Circinusgalaxy, we detected signals at 6120(1) s and 64.2(5) ks. In the longestobservation, the source showed a flux of ~1.1e-13 erg/cm^2/s (absorbed, 0.5-10keV) and the spectrum could be described by a power-law with photon index ~1.4.From archival observations, we found that the luminosity is variable by ~50 percent on time-scales of weeks-years. The two periodicities pin down CXOJ141430.1-651621 as a cataclysmic variable of the intermediate polar subtype.The period of CXOU J141332.9-651756 is 6378(3) s. It is located inside theCircinus galaxy, but the low absorption indicates a Galactic foreground object.The flux was ~5e-14 erg/cm^2/s in the Chandra observations and showed ~50 percent variations on weekly/yearly scales; the spectrum is well fit by a powerlaw ~0.9. These characteristics and the large modulation suggest that CXOUJ141332.9-651756 is a magnetic cataclysmic variable, probably a polar. For CGX-1, we show that if the source is in the Circinus galaxy, its properties areconsistent with a Wolf-Rayet plus black hole binary. We consider theimplications of this for ultraluminous X-ray sources and the prospects ofAdvanced LIGO and Virgo. In particular, from the current sample of WR-BHsystems we estimate an upper limit to the detection rate of stellar BH-BHmergers of ~16 events per yr.

Periodic signals from the Circinus region: two new cataclysmic variables and the ultraluminous X-ray source candidate GC X-1